白藜芦醇对人肾细胞癌786-0细胞PDCD5表达的影响

目的探讨白藜芦醇(Res)对人肾细胞癌786-0细胞中PDCD5蛋白表达的影响及PDCD5蛋白与白藜芦醇抑制人肾细胞癌786-0细胞生长的关系。方法分别采用12.5、25、50、100μmol/L的白藜芦醇(Res)作用于人肾细胞癌786-0细胞系24h.采用免疫细胞化学SP法检测PDCD5蛋白在肾细胞癌786-0细胞中的表达情况;采用流式细胞术检测肾细胞癌786-0细胞的增殖和凋亡情况。结果 Res呈剂量依赖性抑制人肾细胞癌786-0细胞的增殖;人肾细胞癌786-0细胞低水平表达PDCD5,经Res作用以后人肾细胞癌786-0细胞中PDCD5蛋白的表达明显升高,与对照组比较,差异有显著性(P均0.05)。Res各组间比较,12.5μmol/L与25、50及100mol/L比较,差异有显著性(P均0.05);但25μmol/L与50、100μmol/L比较,差异无统计学意义(P0.05)。流式细胞术显示,Res通过阻滞人肾细胞癌786-0细胞于S期而抑制细胞分裂。结论白藜芦醇可以通过上调人肾癌786-0细胞PDCD5蛋白的表达,使786-0细胞阻滞在S期而诱导凋亡,并且这种作用具有浓度依赖性。     

EGCG增强人鼻咽癌细胞对化疗药物的敏感性分析

目的探讨表没食子儿茶素没食子酸酯（EGCG）对鼻咽癌细胞耐药的逆转作用。方法采用浓度梯度诱导建立对紫杉醇（TAX）耐药的鼻咽癌（KB）细胞株,SRB法测定其对TAX的敏感性;Western blot检测P-糖蛋白（P-gp）的表达情况。随后用1μmol/L EGCG与TAX以及耐药性KB细胞共同孵育,检测P-gp的表达情况以及耐药指数（RI）。结果建立的耐药细胞株对TAX的RI为62.2,P-gp表达水平明显高于对照组（P〈0.05）。EGCG、TAX与耐药性KB细胞共同孵育后,RI指数降至40.5,且P-gp蛋白表达水平明显降低（P〈0.05）。结论 EGCG能逆转耐药细胞对TAX的耐药性,其机制可能与P-gp表达下调有关。     

亚致死量陡脉冲调节人卵巢癌细胞多药耐药的实验研究

目的研究亚致死量陡脉冲对人卵巢癌多药耐药细胞亚株的杀伤及对多药耐药性的调节，并探讨其可能的作用机制。方法以人卵巢癌细胞亲本株（SKOV3）及多药耐药亚株（SKOV3／ADM）为研究对象，采用60Hz陡脉冲电击处理，甲基噻唑基四唑（MTT）法检测两株细胞的电敏感性及化疗敏感性；逆转录一多聚酶链反应（RT—PCR）法检测耐药亚株中的多药耐药基因（MDR1）mRNA水平，免疫细胞化学法检测其P糖蛋白（P—gP）表达，用透射电镜观察超微结构的改变。结果SKOV3亲本及耐药亚株对陡脉冲电场的电敏感性相近（P=0．642）；亚致死量脉冲处理后的耐药亚株出现：化疗敏感性增强，半效抑制浓度（IC50）值及耐药指数（RI）均减低，MDR1 mRNA水平无显著改变（P=0．947），P—gP蛋白表达强度显著减弱（P=0．001），细胞出现凋亡改变。结论陡脉冲对SKOV3多药耐药亚株亦可有效杀伤；亚致死量陡脉冲可逆转多药耐药，其可能的机制为增加膜渗透性的同时亦可能诱导并持久改变了耐药相关蛋白的正常构象与功能。     

乙肝病毒核心蛋白对TRAIL诱导细胞凋亡的抑制作用研究

目的探讨HBV核心蛋白（HBe）对TRAIL诱导肝细胞凋亡的影响。方法建立能表达HBc蛋白的细胞模型,用生长曲线和TUNEL的方法检测HBc的表达对TRAIL诱导凋亡的影响。结果CCK-8检测结果显示,相同浓度TRAIL作用下,BEL7402-HBc细胞较对照组细胞的生长抑制率明显降低,当作用浓度为10ng／mL时,差异最为显著;TUNEL流式细胞术结果显示,10ng／mL TRAIL处理BELT402-HBe细胞后,与对照组细胞相比凋亡率明显降低（P〈0．01）。结论HBc表达可降低TRAIL诱导肝细胞凋亡的敏感性,证实HBe具有抵抗TRAIL诱导凋亡的生物学活性。     

肾癌摄取11C-乙酸的分子机制及相关研究

目的：11C-乙酸（11C-AC）PET/CT诊断肾细胞癌的灵敏度高于18F-脱氧葡萄糖（18F-FDG）,但其显像机制尚不明确。本研究探讨其被肾细胞癌摄取是否与细胞膜脂肪酸合成相关。方法①细胞抑制实验：培养3株肾癌细胞（786-0、ACNH和Caki-1）,分别以脂肪酸合酶（FAS）抑制剂C75、二甲基亚砜（DMSO）预处理后加入11C-AC,30 min后测细胞摄取放射性计数,并收集细胞提取液测定蛋白浓度,以蛋白免疫印迹检测FAS表达。②小动物PET/CT显像：对786-0荷瘤裸鼠行11C-AC显像,测得肿瘤与软组织的靶本比（T/B）,处死裸鼠,取肿瘤组织,免疫组织化学检测FAS表达。结果786-0细胞株实验组比对照组摄取11C-AC量明显降低,每微克蛋白的放射性摄取值分别为2.430±0.107和3.544±0.443（P=0.013）,降低率为31.42%。蛋白免疫印迹实验显示,实验组FAS表达明显低于对照组。ACNH和Caki-1细胞株实验组与对照组每微克蛋白的放射性摄取和FAS表达均无显著差异。小动物PET/CT显示,裸鼠皮下肿瘤11C-AC摄取明显增高,肿瘤免疫组织化学检测FAS表达强阳性。结论肾透明细胞癌原发灶的11C-AC摄取与FAS表达有关,但不同病理类型摄取乙酸的程度不同。     

榭皮素对耐长春新碱U251／Vin细胞多药耐药的逆转作用

目的探讨榭皮素对耐长春新碱U251恶性胶质瘤细胞（U251／Vin）多药耐药的逆转作用及机制。方法MTY法检测榭皮素对U251及其耐药株（U251／Vin）细胞的生长抑制率、半数抑制浓度（IC50）、逆转长春新碱耐药倍数,并绘制生长抑制率曲线,用酶联免疫吸附法测定P-糖蛋白（P-gp）、多药耐药相关蛋白（MRP）的表达。结果榭皮素对U251及U251／Vin细胞72h的Ic。分别为（3．80±0．05）、（4．50±0．08）mmol／L,两者比较无统计学差异（P〉0．05）;榭皮素作用后,U251／Vin细胞的IC50值由作用前的（5．435±0．063）μmol／L下降为（0．023±0．004）μmol／L（P〈0．01）,与不耐药的U251细胞IC50值（0．014±0．001）μmol／L接近（P〉0．05）。加入榭皮素后U251／Vin细胞P—gP、MRP蛋白的IC50值比较有统计学差异（P均〈0．05）。结论榭皮素可逆转U251／Vin细胞对长春新碱的耐药,并使P-gp、MRP的IC50降低,提示榭皮素是一种有效的肿瘤多药耐药逆转剂。     

睾丸孤核受体4对前列腺癌PC-3细胞依托泊苷化疗敏感性的影响

目的研究睾丸孤核受体4（TR4）基因对前列腺癌PC-3细胞依托泊苷（VP16）化疗敏感性的影响。方法观察VP16处理后PC-3细胞TR4基因的表达变化;建立TR4过表达的PC-3细胞系,利用MTT法测药物半数抑制剂量（IC50）、细胞存活率,流式细胞仪检测细胞凋亡,观察不同TR4表达水平的PC-3细胞VP16化疗敏感性的差异。结果VP16处理后,PC-3细胞TR4基因表达升高[（0．42±0．02）vs（0．58±0．08）;t=3．30,P〈0．05]。TR4过表达的PC-3细胞VP16IC50升高[（30．83±1．32）μg/ml vs（98．89±4．21）μg/ml;F=20．38,P〈0．05]。VP16作用下,TR4过表达PC-3胞存活率较普通PC-3细胞升高,细胞凋亡则下降[（0．49±0．06）vs（0．18±0．04）;t=7．80,P〈0．05]。结论TR4降低前列腺癌PC-3细胞对化疗药物VP16的敏感性。     

TRAIL对人多发性骨髓瘤细胞株RPMI8226黏附和凋亡的影响及其作用机制的初步探讨

本研究探讨肿瘤坏死因子相关凋亡诱导配体TRAIL对人多发性骨髓瘤细胞系RMPI8226的生长抑制作用,对细胞黏附和凋亡的影响及其作用机制。用MTT法检测TRALL对RPMI8226黏附功能和生长的影响;用AnnexinⅤ/PI检测细胞凋亡;流式细胞学检测细胞表面黏附分子的表达;RT-PCR法测定凋亡相关基因表达水平和Western blot法检测凋亡相关蛋白表达。结果表明:TRAIL抑制RPMI8226细胞生长;可诱导RPMI8226细胞凋亡,并伴有抗凋亡基因Mcl-1、XIAP、cFLIP、CARP1、CARP2和Bcl-2mRNA表达水平下降,促凋亡基因Bax mRNA表达水平升高;RPMI8226细胞内的凋亡执行蛋白caspase-3和NF-κB P65(RelA)表达水平随TRAIL浓度的增加而下降。此外,TRAIL明显上调了RPMI8226细胞表面黏附分子CXCR4的表达。结论TRAIL上调人多发性骨髓瘤细胞株RPMI8226细胞表面的黏附分子CXCR4表达水平。TRAIL可诱导人多发性骨髓瘤细胞株RPMI8226凋亡。在一定的浓度范围内,TRAIL对人骨髓瘤细胞株RPMI8226的生长抑制呈时间-剂量依赖性。     

毛细管电泳免疫-激光诱导荧光术测定甲氨蝶呤对映体耐药A549细胞株中叶酰聚谷氨酸合成酶

目的 为观察甲氨蝶呤(MTX)对映体诱导肺癌A549细胞株耐药后叶酰聚谷氨酸合成酶(folylpolyglutamate synthetase,FPGS)含量变化,建立一种用毛细管电泳免疫-激光诱导荧光术(CEIA-LIF)测定FPGS的方法,以便为深入探讨肿瘤耐药机制提供新的实验手段.方法 实验分别选用耐药浓度为25 μmol/L的L-(+)-MTX和D-(-)-MTX肺癌A549耐药细胞株,以MTX敏感的细胞株作对照,培养获取上述3株细胞,并粗提取FIGS做CEIA-LIF和免疫印迹(WB)实验;用异硫氰酸荧光素(FITC)标记FPGS抗体,与提取的FPGS进行免疫反应;然后采用CEIA-LIF,根据不同分子量蛋白具有不同的迁移时间,分离检测标记蛋白,检测L广(+)-MTX和D-(-)-MTX作用耐药前后3株肺癌A549细胞株中FPGS表达含量;同时用WB作对照,以评价CEIA-LIF的特异性和FPGs定量的准确性.结果 CEIA-LIF分离标记FPGS抗体与免疫复合物的分离时间分别为7.1、8.9 min,分离度(R)=4.5,在10 min内即完成蛋白的分离和检测.经WB鉴定3株细胞液氮冻融裂解后离心提取液中组分与FPGS抗体无非特异性条带出现.CEIA-LIF测定敏感细胞株的检测下限为0.68 mg/μl细胞;而其检测25 μmol/L L(+)-MTX和25 μmol/L D-(-)-MTX诱导耐药细胞中FPGS的表达含量分别为对照组敏感细胞的46.59%和48.36%.结论 本研究建立的CEIA-LIF检测FPGS法具有高效快速的特点,且具与WB类似的特异性;同时提高了检测的敏感度.L-(+)-MTX和D-(-)-MTX诱导耐药后细胞株中FPGS表达含量较敏感细胞株明显减少,证明MTX耐药细胞株FPGS表达含量受损.     

蛇床子素联合TRAIL诱导人卵巢癌细胞的凋亡及其相关机制

目的 探讨蛇床子素联合TRAIL诱导人卵巢癌细胞的凋亡及其相关机制。方法 人卵巢癌细胞株SKOV-3与OVCAR-3各分为四组,分别为蛇床子素组（OS组）,TRAIL组（TR组）,蛇床子素联合TRAIL组（OT组）,空白对照组（Blank组）。各组分别以MTT法检测细胞活力,流式细胞术检测细胞凋亡,ELISA检测caspase-3、caspase-9活化和细胞色素C表达相对水平,Western blot检测凋亡酶激活因子（Apaf-1）相对表达水平。免疫共沉淀法检测Apaf-1和caspase-9前体的相互作用,通过转染Apaf-1siRNA探究Apaf-1对卵巢癌细胞凋亡的影响。结果与空白对照组相比,另外三组卵巢癌细胞活性更低,凋亡率更高,其中蛇床子素联合TRAIL组卵巢癌活性抑制与凋亡促进相对于蛇床子素组和TRAIL组更为显著;TRAIL组中Apaf-1相对水平较空白对照组无明显差异,而蛇床子素联合TRAIL组中Apaf-1高表达;TRAIL组细胞色素C相对水平呈高表达,蛇床子素组与空白对照组细胞色素C、caspase-9前体蛋白表达相对水平一致,而联合TRAIL后,caspase...     

X-linked inhibitor of apoptosis protein inhibition induces apoptosis and enhances chemotherapy sensitivity in human prostate cancer cells

Androgen-insensitive prostate cancer cells are highly resistant to several chemotherapeutic drugs and are characterized by the appearance of apoptosis-resistant cells. In this study, we identified the critical role of X-linked inhibitor of apoptosis protein (XIAP), a potent antiapoptotic factor, in conferring chemotherapy resistance in an androgen-insensitive DU145 human prostate cancer cell line. Results reveal that DU145 cells were highly resistant to cisplatin, but this resistance was overridden when the cells were treated for a prolonged time (>96 hours) with cisplatin (IC(50) = 27.5 to 35.5 micromol/L). A decrease in levels of XIAP and Akt/phospho-Akt and an increase in caspase-3 activity were identified to be key factors in cisplatin sensitivity (40% to 55% decrease in cell viability) at later time points. In contrast, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment caused a 40% to 50% decrease in cell viability within 6 hours (IC(50) = 135 to 145 ng/mL). However, increasing concentrations or prolonged treatment with TRAIL did not change drug potency. A significant increase in caspase-3 activity was observed with TRAIL treatment with no apparent change in XIAP levels. Specific inhibition of XIAP expression using an antisense XIAP phosphorodiamidate morpholino oligomer induced apoptosis and increased caspase-3 activity. Combination of cisplatin with XIAP antisense potentiated cisplatin sensitivity by decreasing the IC(50) from >200 micromol/L with cisplatin alone to 9 to 20 micromol/L and decreasing incubation time required for activity from 96 to 24 hours. Similarly, TRAIL in combination with XIAP antisense phosphorodiamidate morpholino oligomer enhanced TRAIL potency by 12- to 13-fold. In conclusion, abrogation of XIAP expression is essential for therapeutic apoptosis and enhanced chemotherapy sensitization in androgen-refractory prostate cancer cells.     

TRAIL联合Res对乳腺癌MDA-MB-231细胞DR和Caspase表达的影响

目的研究TRAIL联合白藜芦醇（Res）对乳腺癌MDA-MB-231细胞DR和caspase表达的影响。方法MTT法检测细胞增殖;流式细胞术检测细胞凋亡及细胞表面DR4、DR5蛋白的表达;分光光度法检测caspase-3、caspase-8相对活性;荧光定量PCR检测DR4、DR5及caspase-3、caspase-8 mRNA的表达。结果50μmol／L和100μmo/L,Res分别与50ng／mL TRAIL联合作用后,对MDA-MB-231细胞增殖的抑制率及细胞凋亡率分别与单独应用相应浓度的Res和TRAIL比较,均存在显著差异（P〈0．01）。50μmol／L和100μmol／LRes分别与50ng／mLT RAIL联合作用后,caspase-3、caspase-8的相对活性与对照组及单用TRAIL、Res比较均明显增强,差异显著（P〈0．01）。Res作用后,细胞表面DR4、DR5荧光指数与对照组比较明显增强。荧光定量PCR结果显示与对照组比较．Res作用后DR4、DR5mRNA表达上调;与单独用药比较,TRAIL联合Resetcagpase-3、easpase-8 mRNA表达上调。结论TRAIL和Res联合应用对诱导乳腺癌MDA-MB-231细胞凋亡具有明显的协同效果,其作用机制可能与增加DR和caspase活性有关。     

Reversal of galectin-1 gene silencing on resistance to cisplatin in human lung adenocarcinoma A549 cells

This study aims to investigate reversal of Galectin-1 gene silencing on resistance to cisplatin in human lung adenocarcinoma A549 (or A549/DDP) in vivo and in vitro. The stably transfected lentivirus vector was used to silence Galectin-1 in human lung adenocarcinoma cell line A549 and A549/DDP cells and the cell lines were cultured and passaged. RT-PCR and western blot assay were used to test A549, A549/DDP cells, silenced Galectin-1A549 (A549/I) cells, Galectin-1 mRNA and protein expression levels, respectively, in A549/DDP (A549/DDP/I) cells. CCK8 assay was used to measure median inhibitory concentration (IC50) in each group and resistant index of A549/DDP cells and A549/DDP/I cells. Tumor model in nude mice was established by armpit injection of A549, A549/DDP, A549/I, A549/DDP/I cells. Cisplatin was injected intraperitoneally in tumor models and growth of tumor was observed in vivo model. Four weeks later, nude mice were killed and tumor weight and diameter was measured. mRNA and protein expression of Galectin-1 in A549/DDP cells was higher than that in A549 cells. mRNA and protein expression of Galectin-1 in A549/DDP/I cells was lower than that in A549/DDP cells. Moreover, IC50 values ​​and resistance index in A549/DDP cells was higher than that in A549 cells group and IC50 values ​​and resistance index A549/DDP/I cell group were lower than that in A549/DDP cells. Additionally, tumor weight and volume in A549/DDP/I cell group were lower than that in A549/DDP. In conclusion, Galectin-1 gene silencing would improve the sensitivity of A549/DDP cells to cisplatin in vivo and in vitro.     

人胰腺癌5-Fu耐药细胞株的诱导建立及细胞学特性研究

目的建立稳定传代的抵抗5-Fu的人胰腺癌细胞株MiaPaca2-5-Fu,并对细胞生物学特性进行研究。方法逐步增加培养基中5-Fu的浓度,建立对5-Fu耐药的人胰腺癌细胞株MiaPaca2-5-Fu;采用WST法计算出MiaPaca2和MiaPaca 2-5- Fu的半数抑制浓度(IC50)和耐药指敷(RI);检测MiaPaca2和MiaPaca2-5-Fu的生长曲线,计算2个细胞系的倍增时间并进行比较,用流式细胞仪技术检测其细胞周期。结果5-Fu对MiaPaca2和MiaPaca2-5-Fu的IC50分别为(4.29±0.15)μg/mL、(41.55±2.79)μg/mL,RI为9.68(P=0.0019)。根据生长曲线计算出MiaPaca2和MiaPaca2-5-Fu的倍增时间分别为(39.52±0.32)h、(43.27±0.33)h(P=0.0069),2细胞株的G0/G1期、S期、G2/M期均存在显著性差异(P<0.01)。结论成功建立了对5-Fu耐药的人胰腺癌细胞系MiaPaca2-5-Fu,耐药性能明显、稳定,适合于胰腺癌中5-Fu耐药机制的研究。     

Acquired resistance to TRAIL-induced apoptosis in human ovarian cancer cells is conferred by increased turnover of mature caspase-3

Little is known on how cancer cells can acquire resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). In this study, we established TRAIL-resistant cells from the TRAIL-sensitive human ovarian carcinoma cell line OVCAR3 to evaluate the potential mechanisms of acquired resistance to TRAIL. The selected resistant cells were cross-resistant to Fas ligand but remained sensitive to drug-induced apoptosis. Expression of TRAIL receptors was not altered in TRAIL-resistant OVCAR3 cells. Cleavage of caspase-8 and caspase-3 occurred in both TRAIL-resistant and TRAIL-sensitive cells. However, mature caspase-3 fragments were not detected by immunoblot in TRAIL-resistant cells and caspase-3 activity was significantly inhibited in these cells. The addition of proteasome inhibitors significantly increased TRAIL-induced apoptosis in resistant cells and enhanced the accumulation of mature caspase-3 fragments. Pretreatment with cycloheximide showed that active caspase-3 fragments have a high turnover rate in OVCAR3 R350 cells. X-linked inhibitor of apoptosis down-regulation by RNA interference also increased the accumulation of cleaved caspase-3 intermediates and resensitized TRAIL-resistant cells. Our findings show that altered turnover of mature caspase-3 may lead to acquired TRAIL resistance in ovarian cancer cells. Proteasome and X-linked inhibitor of apoptosis inhibitors could have a role in clinical situations to potentiate the cytotoxic effects of TRAIL in resistant tumor cells.     

In vitro evaluation of dimethane sulfonate analogues with potential alkylating activity and selective renal cell carcinoma cytotoxicity

We identified five structurally related dimethane sulfonates with putative selective cytotoxicity in renal cancer cell lines. These compounds have a hydrophobic moiety linked to a predicted alkylating group. A COMPARE analysis with the National Cancer Institute Anticancer Drug Screen standard agent database found significant correlations between the IC50 of the test compounds and the IC50 of alkylating agents (e.g., r = 0.68, P < 0.00001 for chlorambucil). In this report, we examined whether these compounds had activities similar to those of conventional alkylating agents. In cytotoxicity studies, chlorambucil-resistant Walker rat carcinoma cells were 4- to 11-fold cross-resistant to the test compounds compared with 14-fold resistant to chlorambucil. To determine effects on cell cycle progression, renal cell carcinoma (RCC) line 109 was labeled with bromodeoxyuridine prior to drug treatment. Complete cell cycle arrest occurred in cells treated with an IC90 dose of NSC 268965. p53 protein levels increased as much as 5.7-fold in RCC line 109 and as much as 20.4-fold in breast cancer line MCF-7 following an 18-hour drug exposure. Finally, DNA-protein cross-links were found following a 6-hour pretreatment with all compounds. Thus, the dimethane sulfonate analogues have properties expected of some alkylating agents but, unlike conventional alkylating agents, appear to possess activity against RCC.     

RNA干扰核糖核苷酸还原酶M2对耐药卵巢癌细胞凋亡及侵袭性的影响

目的探讨RNA干扰核糖核苷酸还原酶M2(RRM2)对耐药卵巢癌细胞凋亡及侵袭性的影响。方法将RRM2基因的特异性小干扰(siRNA)转染SKOV3/DDP设为干扰组,SKOV3/DDP细胞、SKOV3/DDP-RRM2非特异性阴性细胞设为空白组、阴性组。检测细胞增殖抑制率,计算RI、耐药转染率,荧光PCR技术检测RRM2基因mRNA表达,并分析siRNA转染对SKOV3/DDP耐药指数、RRM2蛋白的影响,采用Transwell观察SKOV3/DDP细胞侵袭能力。结果空白组、阴性组及干扰组转染率均90%。DDP对SKOV3/DDP细胞属低度耐药,吉西他滨对SKOV3/DDP细胞仍较为敏感。DDP、吉西他滨对干扰组、阴性组、空白组的DDP对细胞的半数抑制浓度(IC50)值比较,差异有统计学意义(P0.05),DDP、吉西他滨对干扰组细胞的IC50值显著低于阴性组、空白组(P0.05)。SKOV3/DDP细胞、SKOV3细胞RRM2蛋白的相对表达量比较,差异有统计学意义(P0.05),且转染Ⅰ组、Ⅱ组、Ⅲ组相对表达量均显著低于阴性组、空白组,其中以转染Ⅰ组细胞的RRM2蛋白相对表达量下降最显著(P0.05)。干扰组细胞凋亡率显著高于空白组、阴性组,穿膜细胞数显著低于空白组、阴性组(P0.05)。结论 siRNA可有效抑制RRM2基因在卵巢癌中的增殖与侵袭性,增加耐药细胞的药物敏感性,尤其是促进DDP诱导的耐药细胞凋亡。     

HPMA copolymers containing doxorubicin bound by a proteolytically or hydrolytically cleavable bond: comparison of biological properties in vitro.

N-(2-Hydroxypropyl)methacrylamide (HPMA) copolymer carrier containing the anticancer drug doxorubicin bound either by a proteolytically degradable bond (non-targeted PK1 or targeted with alpha-CD71 mAb) or by a hydrolytically degradable bond were synthesised and tested in vivo for various biological properties. Mouse 38C13 B-cell lympoma was used as a well established and defined cell line for this study. 38C13 cells are sensitive to free doxorubicin and IC50 was very low, about 0.014 microM. PK1 showed a strongly decreased cytostatic effect, IC50 being 12.6 microM. alpha-CD71 targeted conjugate, which can be considered as an antibody-targeted form of PK1, had IC50 0.358 microM. HPMA copolymer with doxorubicin bound via a hydrolytically sensitive bond (HYD conjugate) showed a high cytostatic effect with IC50 about 0.052 microM. We demonstrated that HYD conjugate inhibited DNA synthesis and induced p21(Waf1/Cip1) protein expression (p21(Waf1/Cip1) is cyclin-dependent kinase inhibitor which blocks cell cycle progression) as quickly as free doxorubicin, whereas PK1 acted much more slowly. Similarly, apoptosis induction measured by Annexin V binding and Caspase 3 activity was detected later after incubation of cells with PK1 or alpha-CD71 targeted conjugate. Apoptosis was manifested by elevation of bax and bad mRNA levels, which was much more rapid and intense in the case of free doxorubicin and HYD conjugate. Expression of antiapoptotic genes as well as cyclin-dependent kinases was surprisingly not affected.